/*
 * Copyright 2014 Google Inc. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.ebt.m.widget;

import android.content.Context;
import android.graphics.Typeface;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.util.SparseArray;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.HorizontalScrollView;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.ebt.m.R;

public class SlidingTabLayout extends HorizontalScrollView {

    public interface TabColorizer {

        /**
         * @return return the color of the indicator used when {@code position}
         * is selected.
         */
        int getIndicatorColor(int position);

    }

    private static final int TITLE_OFFSET_DIPS = 80;
    private static final int TAB_VIEW_PADDING_DIPS = 12;
    private static final int TAB_VIEW_TEXT_SIZE_SP = 14;

    private int mTitleOffset;

    private int mTabViewLayoutId;
    private int mTabViewTextViewId;
    private boolean mDistributeEvenly;
    private boolean mDistributeEvenlyWhenWidthNotFull;
    private int mSlidingTabLayoutContentWidth;

    private ViewPager mViewPager;
    private SparseArray<String> mContentDescriptions = new SparseArray<String>();
    private ViewPager.OnPageChangeListener mViewPagerPageChangeListener;

    private final SlidingTabStrip mTabStrip;

    public SlidingTabLayout(Context context) {
        this(context, null);
    }

    public SlidingTabLayout(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public SlidingTabLayout(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        // Disable the Scroll Bar
        setHorizontalScrollBarEnabled(false);
        // Make sure that the Tab Strips fills this View
        setFillViewport(true);

        mTitleOffset = (int) (TITLE_OFFSET_DIPS * getResources().getDisplayMetrics().density);

        mTabStrip = new SlidingTabStrip(context);
        addView(mTabStrip, LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
    }

    public void setCustomTabColorizer(TabColorizer tabColorizer) {
        mTabStrip.setCustomTabColorizer(tabColorizer);
    }

    public void setDistributeEvenly(boolean distributeEvenly) {
        mDistributeEvenly = distributeEvenly;
    }

    public void setDistributeEvenlyWhenWidthNotFull(boolean distributeEvenly, int slidingTabLayoutContentWidth){
        mDistributeEvenlyWhenWidthNotFull = distributeEvenly;
        mSlidingTabLayoutContentWidth = slidingTabLayoutContentWidth;
    }

    /**
     * Sets the colors to be used for indicating the selected tab. These colors
     * are treated as a circular array. Providing one color will mean that all
     * tabs are indicated with the same color.
     */
    public void setSelectedIndicatorColors(int... colors) {
        mTabStrip.setSelectedIndicatorColors(colors);
    }

    public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) {
        mViewPagerPageChangeListener = listener;
    }

    /**
     * Set the custom layout to be inflated for the tab views.
     *
     * @param layoutResId Layout id to be inflated
     * @param textViewId  id of the {@link TextView} in the inflated view
     */
    public void setCustomTabView(int layoutResId, int textViewId) {
        mTabViewLayoutId = layoutResId;
        mTabViewTextViewId = textViewId;
    }

    /**
     * Sets the associated view pager. Note that the assumption here is that the
     * pager content (number of tabs and tab titles) does not change after this
     * call has been made.
     */
    public void setViewPager(ViewPager viewPager) {
        mTabStrip.removeAllViews();

        mViewPager = viewPager;
        if (viewPager != null) {
            viewPager.setOnPageChangeListener(new InternalViewPagerListener());
            populateTabStrip();
        }
    }

    /**
     * Create a default view to be used for tabs. This is called if a custom tab
     * view is not set via {@link #setCustomTabView(int, int)}.
     */
    protected TextView createDefaultTabView(Context context) {
        TextView textView = new TextView(context);
        textView.setGravity(Gravity.CENTER);
        textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, TAB_VIEW_TEXT_SIZE_SP);
        textView.setSingleLine();//单行显示
        textView.setTypeface(Typeface.DEFAULT);
        textView.setLayoutParams(new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));

        TypedValue outValue = new TypedValue();
        getContext().getTheme().resolveAttribute(android.R.attr.selectableItemBackground, outValue, true);
        textView.setBackgroundResource(outValue.resourceId);
        textView.setTextColor(getResources().getColorStateList(R.color.tab_selector));
        textView.setAllCaps(true);

        int padding = (int) (TAB_VIEW_PADDING_DIPS * getResources().getDisplayMetrics().density);
        textView.setPadding(padding, padding - 2, padding, padding - 2);

        return textView;
    }

    private void setCustomViewParams(TextView textView) {
        textView.setGravity(Gravity.CENTER);
        textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, TAB_VIEW_TEXT_SIZE_SP);
        textView.setTypeface(Typeface.DEFAULT);
        textView.setLayoutParams(new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));

        TypedValue outValue = new TypedValue();
        getContext().getTheme().resolveAttribute(android.R.attr.selectableItemBackground, outValue, true);
        textView.setBackgroundResource(outValue.resourceId);
        textView.setTextColor(getResources().getColorStateList(R.color.tab_selector));
        textView.setAllCaps(true);

        int padding = (int) (TAB_VIEW_PADDING_DIPS * getResources().getDisplayMetrics().density);
        textView.setPadding(padding, padding - 2, padding, padding - 2);

    }

    private void populateTabStrip() {
        final PagerAdapter adapter = mViewPager.getAdapter();
        final OnClickListener tabClickListener = new TabClickListener();

        //修复在设置even模式后，当字体过小时，较宽的tab被压缩的bug
        int specW = MeasureSpec.makeMeasureSpec(Integer. MAX_VALUE>>2, MeasureSpec.AT_MOST);
        int widthSum = 0;
        int adapterCount = adapter.getCount();
        int[] childrenWidths = new int[adapterCount];
        View[] childrenViews = new View[adapterCount];

        for (int i = 0; i < adapterCount; i++) {
            View tabView = null;
            TextView tabTitleView = null;

            if (mTabViewLayoutId != 0) {
                // If there is a custom tab view layout id set, try and inflate
                // it
                tabView = LayoutInflater.from(getContext()).inflate(mTabViewLayoutId, mTabStrip, false);
                tabTitleView = (TextView) tabView.findViewById(mTabViewTextViewId);
            }

            if (tabView == null) {
                tabView = createDefaultTabView(getContext());
            } else {
                setCustomViewParams(tabTitleView);
            }

            if (tabTitleView == null && TextView.class.isInstance(tabView)) {
                tabTitleView = (TextView) tabView;
            }

            if (mDistributeEvenly) {
                LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) tabView.getLayoutParams();
                lp.width = 0;
                lp.weight = 1;
            }

            tabTitleView.setText(adapter.getPageTitle(i));
            tabView.setOnClickListener(tabClickListener);
            String desc = mContentDescriptions.get(i, null);
            if (desc != null) {
                tabView.setContentDescription(desc);
            }

            mTabStrip.addView(tabView);
            if (i == mViewPager.getCurrentItem()) {
                tabView.setSelected(true);
            }

            childrenViews[i] = tabTitleView;
            tabTitleView.measure(specW, 0);
            childrenWidths[i] = tabTitleView.getMeasuredWidth();
            widthSum += childrenWidths[i];
        }

        //rick 如果小于总宽度，且设置了均匀分布充满整个宽度的模式
        if (widthSum < mSlidingTabLayoutContentWidth){
            if(mDistributeEvenlyWhenWidthNotFull){
                int extra = (mSlidingTabLayoutContentWidth - widthSum) / adapterCount;
                for (int i = 0; i < adapterCount; i++) {
                    int height = LinearLayout.LayoutParams.MATCH_PARENT;
                    if (childrenViews[i].getLayoutParams() != null){
                        height = childrenViews[i].getLayoutParams().height;
                    }
                    LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(childrenWidths[i] + extra, height);
                    lp.weight = 0;
                    childrenViews[i].setLayoutParams(lp);
                }
            }
        }
    }

    public void setContentDescription(int i, String desc) {
        mContentDescriptions.put(i, desc);
    }

    public TextView getTextViewByPosition(int position) {
        try {
            if (mTabStrip != null && mTabStrip.getChildCount() > 0) {
                return (TextView) mTabStrip.getChildAt(position);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    public void updateTitleByPos(int position, String title) {
        try {
            if (mTabStrip != null && mTabStrip.getChildCount() > 0) {
                TextView titleTv = (TextView) mTabStrip.getChildAt(position);
                titleTv.setText(title);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();

        if (mViewPager != null) {
            scrollToTab(mViewPager.getCurrentItem(), 0);
        }
    }

    private void scrollToTab(int tabIndex, int positionOffset) {
        final int tabStripChildCount = mTabStrip.getChildCount();
        if (tabStripChildCount == 0 || tabIndex < 0 || tabIndex >= tabStripChildCount) {
            return;
        }

        View selectedChild = mTabStrip.getChildAt(tabIndex);
        if (selectedChild != null) {
            int targetScrollX = selectedChild.getLeft() + positionOffset;

            if (tabIndex > 0 || positionOffset > 0) {
                // If we're not at the first child and are mid-scroll, make sure
                // we obey the offset
                targetScrollX -= mTitleOffset;
            }

            scrollTo(targetScrollX, 0);
        }
    }

    private class InternalViewPagerListener implements ViewPager.OnPageChangeListener {
        private int mScrollState;

        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
            int tabStripChildCount = mTabStrip.getChildCount();
            if ((tabStripChildCount == 0) || (position < 0) || (position >= tabStripChildCount)) {
                return;
            }

            mTabStrip.onViewPagerPageChanged(position, positionOffset);

            View selectedTitle = mTabStrip.getChildAt(position);
            int extraOffset = (selectedTitle != null) ? (int) (positionOffset * selectedTitle.getWidth()) : 0;
            scrollToTab(position, extraOffset);

            if (mViewPagerPageChangeListener != null) {
                mViewPagerPageChangeListener.onPageScrolled(position, positionOffset, positionOffsetPixels);
            }
        }

        @Override
        public void onPageScrollStateChanged(int state) {
            mScrollState = state;

            if (mViewPagerPageChangeListener != null) {
                mViewPagerPageChangeListener.onPageScrollStateChanged(state);
            }
        }

        @Override
        public void onPageSelected(int position) {
            if (mScrollState == ViewPager.SCROLL_STATE_IDLE) {
                mTabStrip.onViewPagerPageChanged(position, 0f);
                scrollToTab(position, 0);
            }
            for (int i = 0; i < mTabStrip.getChildCount(); i++) {
                mTabStrip.getChildAt(i).setSelected(position == i);
            }
            if (mViewPagerPageChangeListener != null) {
                mViewPagerPageChangeListener.onPageSelected(position);
            }
        }

    }

    private class TabClickListener implements OnClickListener {
        @Override
        public void onClick(View v) {
            for (int i = 0; i < mTabStrip.getChildCount(); i++) {
                if (v == mTabStrip.getChildAt(i)) {
                    mViewPager.setCurrentItem(i);
                    return;
                }
            }
        }
    }

    public SlidingTabStrip getSlidingTabStrip(){
        return mTabStrip;
    }

}
